Anti-Aliasing with rtrace 360° stereo views

1

Hello, I’m rendering 360° stereo views with view360stereo.cal file. To create equirectangular projection Dion Moult work with “rtrace”: $ X=2048; Y=2048; cnt $Y $X | rcalc -f cal/3d360.cal -e “XD=$X;YD=$Y;X=0;Y=0;Z=0;IPD=0.06;EX=0;EZ=0” | rtrace -n NCORES -x $X -y $Y -fac @saved.opt scene.oct > out.hdr. I render image but it have diagonal edges are like staircases. I read that rpict with have a parameter (-pj) for this but in “rtrace” it generate command line error. Are you know any solution for this? Thank you.

Juan Manuel

2

Hi Juan Manuel, the easiest is probably to render with e.g. twice the resolution and downsample with a Gaussian filter by pfilt -x /2 -y /2 -r .7 out.hdr > outNoSteps.hdr to get the desired effect.
Best, Lars.

1 Like
3

Hi Juan,

Lars’ suggestion is a good one, but you can also try modifying “view360stereo.cal” as follows to add some pixel sample jitter. The original code reads:

{ Direction of the current pixel (both angles in radians) }
px = (XD-1)/2 - $2;
py = YD-.5 - $1;

You can try modifying it to:

{ Direction of the current pixel (both angles in radians) }
px = (XD-1)/2 - $2 + 0.6*(1-2*rand(3.5381*recno+17.385));
py = YD-.5 - $1 + 0.6*(1-2*rand(-1.568*recno+4.2874));

The rand(seed) function returns a psuedo-random number based on seed, so we supply a different seed to each call computed from recno, the count of pixels that have been computed. If you don’t want to modify “view360stereo.cal”, you can instead modify your command, using:

cnt $Y $X | rcalc -e '$1=$1+0.6*(1-2*rand(-1.568*recno+4.2874))' -e '$2=$2+0.6*(1-2*rand(3.5381*recno+17.385))' | rcalc -f view360stereo.cal ...

I hope this helps!
-Greg

1 Like
4

Hi Greg, thank you very much. I will try with both solution. And I let you know the results.

5

Hi Lars, thank you very much. I will try with this solution too.

6

Combining the two suggestions (over-sampling and filtering with pfilt plus jittered sampling) will look best.